Chrome user having major issues and out of ideas!

[twinspoolin94]

So for shits and giggles I took the stock rom and turned off the needed cels, scaled the injectors and took it for a ride. Its not perfect but greg is right it drives like a stock car even with the hotwired 340 and 850's. it does run on the rich side and is a bit choppy but it is 10 times better than it was with the tune. I even got it to idle somewhat normal even though its still hunts but that is what I would expect with the fuel situation and untuned.

[twinspoolin94]

I think we may have found something. Just checked under the hood and there is a sticker that says the vehicle conforms to federal EPA standards AND CA standards, which would indicate that my 96 is a cali spec car. I am all but sure I ordered an ECU for Federal. How do I fix this?

[twinspoolin94]

MAF settings

Montero 482
scaled 357.5
0
25
50
75
100
125
150
175
200
225
250
275
300
400
500
600
800
1000
1200
1400
1600

0
25.078125
50.15625
75.234375
100.3125
125.390625
150.46875
175.546875
200.625
224.44921875
249.52734375
274.60546875
299.68359375
319.74609375
319.74609375
319.74609375
319.74609375
319.74609375
319.74609375
319.74609375
319.74609375


Fuel injectors FIC 850's scalled at 839 (closest the rom could get) 3.2 ohm impendance
Voltage
4.6875
7.03125
7.9833984375
10.0341796875
12.01171875
13.9892578125
15.966796875

MS
3.825
3.825
3.735
2.37
1.74
1.395
1.155

[twinspoolin94]

So I am more confused than ever now. I switched the jumpers to set it as a cali spec ecu and started the car and the fuel trims go opposite lock. put the jumpers back to federal ( how the ecu came) and it goes ape shit with both low fuel trims maxing at -12. What is confusing me is I checked the vin and this is a Cali spec car. It had the grey ecu case indicating it was the recalled ecu. So at this point......Im lost. I am on the original wiring harness if that helps.

[Jimvr4]

Do you have 4 o2 sensors? Cal spec cars do. One before each precat and two in the down pipe.

[twinspoolin94]

yep 4 sensors

[twinspoolin94]

So I ended up ordering an AEM FPR just so I can rule out overrun. found something interesting, if i reset the ecu by removing the neg battery cable it will drive several miles perfectly. no cutting out, steady idle, and smooth shifts. The low fuel trims will go progressivly negative until maxing out. Then car will start running like it is drowning in fuel and the AFR will show around 11 at idle but bouncing up and down like it is trying to adjust it back leaner. Lows are fine and car drives fine down the highway at steady speed unless I let of gas or I am trying to feather it to maintain a steady speed. when driving around at low speeds and slight throttle the car bogs and goes of the map lean until I power through it. I can also kill the engine by lightly touching the throttle and holding it, goes lean and dies. When disabling the narrowbands entirely the runs and drives fine, just rich

[Jimvr4]

Its pretty obvious that closed loop is not working properly. When you pull the battery cable the ECU forgets the trims and has to relearn. With the sensors it is reading it eventually maxes the trims and cruises poorly. When you power through it you are open loop and that works.

IMO the FPR change is not going to help anything. What I would do is triple check that you have the correct ECU connections for your left bank and right bank O2 sensors and then verify that indeed they cycle properly in the logs. Set logging to screen, unplug the front sensor and verify that cycling stops, plug in and it resumes. Do the same for the rear sensor.

When you disable the narrowbands entirely you are confirming again that it is a closed loop issue. Check my chrome tuning experience thread. First few pages I went through this issue. It is all too common that the ECU is not set up properly with regard to Cali spec or Fed spec.

[twinspoolin94]

I am very curious about the ECU. After speaking with jester I took the ecu out and switched jumpers over to a cali spec/ all 96/97. o2 go opposite lock so I am sure this is not the right set up. I followed these instructions Chromed ECU | 94-97 US VR4 Plug and Play Flash Ecu Installation If you look at the picture for setting up 96/97 it is set for a cali car but will not work on my 96 that is a cali spec? Doesnt make any sense to me. Am I missing something here?

[twinspoolin94]

One reason I am leaning toward the FPR even though everyone tells me it is highly unlikely is because this problem began immediatly after hotwiring the fuel pump. When I say immediate I mean first time on the highway immediate. I have ruled out problems with the hotwire or wiring so that leaves me with the FPR. I know for a fact I am overruning it based off fuel pressure so for 160 bucks its better for me to rule this out for good.